1. Technical Field
The present invention relates to a method of estimating a spectrum of noise from a sound signal mixed with the noise. Also, the present invention relates to a method and an apparatus for generating sound signals with the above-mentioned noise being suppressed on the basis of the above-mentioned estimation.
2. Related Art
Techniques for estimating, from a sound signal mixed with noise, the spectrum of this noise are used to suppress the noise (namely, noise is removed from a noise-mixed sound signal to take out a target sound signal) in voice recognition technologies and voice communication technologies such as telephony. Technologies for suppressing noise contained in sound signals include a spectral subtraction method for example. In this spectral subtraction method, the spectrum of noise is estimated from a noise-mixed sound signal and the estimated noise spectrum is subtracted from the spectrum of the noise-mixed sound signal, thereby attaining noise suppression.
The related-art technologies based on the spectral subtraction method are disclosed in the following patent documents:
[Patent document 1] Japanese Unexamined Patent Application No. Hei 11-3094
[Patent document 2] Japanese Unexamined Patent Application No. 2002-14694
[Patent document 3] Japanese Unexamined Patent Application No. 2003-223186